Electron discharge device



Dec. 22, 1953 E. J. WALSH 2,663,813

ELECTRON DISCHARGE DEVICE Filed June 15, 1951 2 Sheets-Sheet l IN VENTOR'E.J. WALSH A T TORNEY Dec. 22, 1953 Y E. J. WALSH 2,663,818

ELECTRON DiSCHARGE DEVICE Filed June 15, 1951 2 Sheets-Sheet 2 M/lE/VTOR EJWALSH A T TORNEV Patented Dec. 22, 1953 UNITED STATES,

NT FlQE ELECTRON DISCHARGE DEVICE Application June 15, 1951, Serial No.231,765

16 Claims.

This invention relates to electron discharge devices and, moreparticularly, to the support and mounting of electrodes therefor.

In close-spaced electron discharge devices employing control electrodeswound with exceedingly fine lateral wires, the accuracy of thepositioning of the electrodes, and the ease With which that accuracy canbe reproduced from one device to another in manufacture, are of greatimportance. It is particularly important that the oathode be accuratelypositioned in close proximity to the next element of the device, whichis generally the control electrode. The positioning means employed mustbe firm, allow for the expansion of the cathode at elevated temperatureswithout alteration of the cathode-electrode spacing, but not sap awayfrom the cathode any considerable amounts of power.

It is one object of this invention to accurately and facilely positionand support electrodes in an electron discharge device.

Another object of this invention is to improve the structure of electrondischarge devices.

A further object of this invention is to facilitate the manufacture ofelectron discharge devices.

These and other objects of this invention are accomplished in onespecific illustrative embodiment of this invention in which a ceramic orother insulating block has a central groove therein. The upper surfaceof the block on either side of the groove is stepped, there being aprecisely dimensioned central portion, and two coplanar accuratelydimensioned end portions. A fine wire is wound around the block overboth portions and across the central groove. A cathode having a planarface is then positioned in the central groove and supported by the Wiresacross the lower end portions. The wires across the central portion areseparated from those across the end portion and serve as the laterals ofthe control grid of the device. The cathode is thus suspended from theend wires and its plane face is accurately positioned with respect tothe control grid.

In this one specific embodiment of the invention, the block ispositioned in a cradle, connection being made to the control electrodelaterals by the cradle. A tab advantageously extends across the cradleat each end of the upper surface portion of the block to lock the blockin position and also to shield the cathode ends and the suspension Wiresfrom the field of the anode, which may be positioned adjacent thecentral portion of the block and slightly removed from the controlelectrode laterals.

In another specific embodiment of this invention, the block has only asingle top surface but transverse grooves are cut therein adjacent eachend. Glass frit or other material which seals to the block is placed inthe grooves. A rod is then placed in the grooves and sealed to the blockat a height above the base of the transverse grooves accuratelydetermined to obtain the desired accurate spacing of the cathode and thecontrol electrode wires. The cathode is then supported from thetransverse rod, the control elec trode laterals having been wound aroundthe block and joined thereto.

It is therefore one feature of this invention that the cathode bepositioned from the next electrode in the device by being suspended froma support block: around which the next electrode is wound.

It is a further feature of this invention in accordance with oneembodiment thereof that the support block have two accuratelydimensioned surface levels, the cathode being supported by suspensionmeans extending across one surface level and the electrode wires beingwound around the next surface level.

It is a further feature of this invention in accordance with the oneembodiment thereof that the cathode be suspended by wires Wound aroundthe support block, the Wires advantageously being initiallycontinuations of the electrode wound around the next surface level.

It is a further feature of this invention in ac cordance with anotherembodiment thereof that the cathode be suspended from support rodsaccurately positioned with respect to the upper surface of the supportblock in transverse grooves therein. v

It is a further feature of this invention that the support block besituated in a cradle forming the control electrode connection for thedevice, tabs extending across the cradle and across the last laterals ofthe electrode to lock the support I block in the cradle.

A complete understanding of this invention and of the various featuresthereof may be gained from consideration of the following detaileddescription and the accompanying drawings, in

' which:

Fig. l is a perspective view of an electron discharge device inaccordance with one specific. il-

lustrative embodiment of this invention, a portion of the envelopehaving been broken away;

Fig. 2 is a partial sectional view of the electrode support means of thedevice of Fig. l, illustrative'of one specific embodiment of thisinvention;

Fig. 3 is a sectional view of the device of Fig. 1 along the line 3-3and Fig. 4 is a partial sectional view of an electrode support meansemployable with the device of Fig. l and illustrative of anotherembodiment of this invention.

Referring now to the drawing, the envelope of the electron dischargedevice illustrated in Fig. 1 comprises an upper or anode, glass orvitreous portion or stem l which is joined to an upper electrode disc H,and a lower or cathode, glass portion or stem 12 which is joined to.a:lower electrode disc 13. The cathodeand control electrode mountingmeans comprises a support block 15, advantageously of ceramicsuch as asteatite, having a central groove 16 therein, an upper surface llaccurately dimensioned -and-a stepped or lower surface H3 at each end,also accurately dimensioned. The sides of the support blockl5 adjacentthesurfaces ii and [8 are advantageously beveled.

A hollow planar cathode 2B is supported in the groove l6 by beingsuspended from a plurality of wires 2i, as for example three,.woundaround the lower surface i8 and the block it at each end thereof. Thecathode 28 may be secured to the wiresll by being brazed or weldedthereto. A heater 22 extends through the'hollow cathode 20 and issecured at each end to heater leadsj23 extending through the cathodeglass portion 12. Tabs 25 are advantageously positioned underneath thewound wires2l at each side of each end of the block and serve toelectrically connect the cathode to a cathode lead 26 extendingcentrally through the cathode glass portion 12.

Electrode wires 27 are wound around the block l5 and the surface I!intermediate the two end stepped or lower surfaces it. The cathode 20.advantageously has an electron emissive coating 28, as of barium andstrontium oxides on its surface adjacent and opposite the electrodelaterals 21.

.The support block to together with the .suspended cathode 20 and woundgrid laterals 21 is advantageously seated in a cradle29 advantageouslyformed integral with the lower grid disc The block 15 is locked inposition inthe cradle by bridges or looking members'flfl extendingacross the upper surface llatthe ends thereof and brazed or otherwisesecured to the lower grid disc Hi.

The anode'32 may advantageouslybe aiflat block adjacent the gridlaterals .Z'Lbetween. the bridges 38. The anode. 32 is supported by. ananode lead 33 extending centrally .throughfthe upper glass envelopeportion Iii. The lead..33 is advantageously hollow and serves as theexhaust tubulation for the device, the lead having apertures 34therethrough communicating with the interior of the device.

As the grid wires 2'! are wound completely around the block I5 they arein contact with the cradle 29 and the locking memberstfi which provideelectrical connection between the electrode and the grid discs I! and i3external to the envelope of the device. Tabs, similar to.tabs.2-5, couldhowever be positioned under the grid laterals. 21 at each side of theblock l5 and connected to the cradle 29 of either grid disc H or it.

In the fabrication of this device, the block or support l5 has woundaround it a single very fine wire, suchas of the order 0.00030 inch indiameter, the tabs being held inposition .duringthe winding operation.The wire is then-glazed or otherwise bonded to the block l5. Thecsinglegeously' be placed on the cradle 28.

wire is then separated into three sections, the middle section being theportion of the wire Wound around the upper surface I! and comprising thegrid laterals 2i and the two end sections being the portions of the wirewound around the lower surface it and comprising the wire supports 21.The cathode. 2! is then slipped into the groove to in the block l5 andbrazed or otherwise secured to the wires 2|.

inc cathode and electrode mount is thus a separate single unit which maynext advanta- As is easily seen in Fig. l, the cradle 29 advantageouslyis approximately the same length as the central surface portion ll whichcoincides with the length of the control electrode. The two lockingmembersor-bridges 3d are then welded or otherwise secured to the lowergrid discs i3 so as to extend across the ends of the central surfaceportion I! .and. to bear. against the grid. laterals 21 between .itandthe surface H.

The upper and lower .glass portions lo and i2 are advantageouslyprepared as. separate units,

each having-its associated electrodediscsealed two grid .discslll .and53 being. adjacent each other. The two gridldiscs arewelded, brazed,-orotherwise sealed together; to formthe main seal vof the device. .Thedevice. is...next exhausted through the anode. tubulationlead 33 which.is

. then sealedoif.

Electron discharge devices -in-accordance with this invention.in..whioh.the. cathode .is suspended from the. stepped mountingblockbywires extending across the block assure an accurate spacing 35. betweenthe. cathode coating 28' and theelectro'de laterals 21. because thespacing is dependent on the dimensioning of thesurfaces i1 and i8, whichcan be very accurately and facilely controlled in.-manufacture,. as byfine grinding.

Expansion of the cathode at the temperature of operation will not affectthisspacingSS. Transverse. expansion of the cathodeiil can only cause a.displacement of the lower side of the-cathode,

. removed from the electrode lateralsZl, as the position of theupperside, on which the coating 28 is located, is determined by thesuspensionwires 2!. .These Wires themselves will .not expand materially as'theblockremains cool and thermally insulates them.

Referring now to Fig. 4, there is shownapar- .tial sectional viewillustrative of another rembodiment of this invention. .The supportblock 40, for example of ceramic, has a groove it centrally thereinsimilarto the groove is and in which is located the cathode 26. Theblock 46 however has only-a single upper surface 62 around the centralportion of which are wound the electrode laterals 2?. The block is-alsosimilarly .10- cated in the cradle 29 by the locking members 30. :In theuppersurfacezdz adjacent the-endsof fastened in place -inceachggroove33, 5,5. bym,

powdered glass glazed to the rod and the block. The cathode 2c is thensuspended from the rods 45, as by being clipped thereto.

In the manufacturing of electrode support and mounts in accordance withthis illustrative embodiment of this invention, the rods 45 areaccurately positioned in the grooves 43 and secured in place, as by theglaze 44, to provide a predetermined accurate spacing 46 between thesurface of the electrode coating 28 and the electrode laterals 2?. Whilethe rods 45 may be positioned at the base of the grooves 43, in whichcase the base of the grooves would have to be accurately determined withrespect to the upper surface 42, it is a feature of this embodiment ofthis inven tion, that the accurate spacing 4G is determined by thepositioning of the rods 45 in the grooves 43.

Because the cathode 2B is suspended at each end from the ceramic orother insulating block as, heating of the cathode can cause relativelyno displacement of the cathode coating 28 or variation in the spacing45, for the reasons mentioned above with reference to the embodiment ofFig. 2.

Reference is made of the application of C. T. Goddard, Serial No.231,816, filed June 15, 1951, wherein related inventions are described.

It is to be understood that the above-described arrangements areillustrative of the application of the principle of the invention.Numerous other arrangements may be devised by those skilled in the artwithout departing from the spirit and scope of the invention,

What is claimed is:

1. An electron discharge device comprising a support block having acentral groove therein, a plurality of wire laterals on said block andextending across said groove, a fiat cathode in said groove, and supportmeans including a planar portion extending across said groove at theends thereof, said cathode being suspended directly from said planarportion of said support means.

2. An electron discharge device comprising an insulator block having acentral groove therein and a planar upper surface, a plurality of wirelaterals wound around said block and secured thereto, said wire lateralsextending across said groove in the plane of said surface, a flatcathode in said groove, and support means extending across said grooveat the ends of said block and defining a plane parallel to said planarsurface, said cathode being suspended from said support means in saidplane adjacent said wire laterals.

3. An electron discharge device comprising an envelope, a cradlesupported in said envelope, an insulator block positioned in saidcradle, said block having a central groove therein and a planar uppersurface, a plurality of wire laterals extending across said groove inthe plane of said surface and defining an electrode, a flat cathode insaid groove, support means extending across said groove at the ends ofsaid block and defining a plane adjacent said wire laterals, saidcathode being suspended from said support means in said plane, andlocking members extending across said block and secured to said cradleon each side of said block locking said block in position in saidcradle.

4. An electron discharge device comprising an envelope, a disc extendingthrough said envelope and defining a cradle portion therein, a pluralityof leads extending through the base of said envelope, an insulator blockpositioned in said cradle, said block having a central groove thereinand a planar upper surface, a plurality of wire laterals extendingacross said groove in the plane of said surface and secured to saidblock, said laterals being in electrical contact with said cradle anddefining an electrode, a flat hollow cathode in said groove, supportmeans extending across said groove at each end of said block anddefining a plane adjacent said wire laterals, said cathode beingsuspended from said support means in said plane, a heater elementextending within said cathode, means electrically connecting said heaterelement to certain of said leads in said base, means electricallyconnecting said cathode to another of said leads in said base, lockingmembers extending across said block between said electrode and saidsupport means, said locking members being secured to said disc on eitherside of said cradle portion and locking said block therein, an anodepositioned adjacent said wire laterals to the other side thereof thansaid/cathode, and lead means extending through said envelope andsupporting said anode.

5. An electron discharge device comprising a support block having afirst and a second surface thereon, a first plurality of lateral wiressecured to said block across said first surface and defining anelectrode, a second plurality of lateral wires secured to said blockacross said second surface, and a cathode suspended from said secondplurality of lateral wires in the plane of said second surface adjacentsaid first plurality of lateral wires.

6. An electron discharge device comprising a support block having acentral groove therein, a planar surface thereon and stepped portions ofthe ends thereof, a first plurality of wire laterals secured to saidblock, said laterals extending across said groove in the plane of saidsurface and defining an electrode, a second plurality of wire lateralssecured to said block and extending across said groove in the plane ofsaid stepped portions and a planar cathode in said groove and suspendeddirectly from said second plurality of wires.

'7. An electron discharge device comprising an insulator support blockhaving two parallel surfaces thereon, a plurality of wire lateralssupported by said block, a first portion of said wire laterals being inthe plane of one of said surfaces and defining an electrode, a secondportion of said wires being in the plane of the other of said surfaces,a cathode positioned adjacent said electrode wire laterals and suspendeddirectly from said second portion of said wires, and means electricallyconnecting said electrode laterals together.

8. An electron discharge device comprising an envelope, a cradle membersupported in said envelope, an insulator block in said cradle member,said block having a central groove therein and two parallel planarsurfaces thereon, a plurality of wire laterals secured to said block andextending across said groove, a first portion of said laterals being inthe plane of the upper of said surfaces and defining an electrode, asecond portion of said laterals being in the plane of the lower of saidsurfaces, a fiat cathode in said groove, said cathode being suspendedadjacent said electrode laterals from said second portion of saidlaterals, and locking means extending across said block and secured tosaid cradle memberon each side of said block locking said block inposition in said cradle member.

9. An electron discharge device comprising an envelope, a disc extendingthrough said envelope. a cradle member within said envelope supported bysaid disc and electrically connected thereto; a lead extending throughthe -base:=of said envelope, an insulator block positioned in 's'a-idcradle, said block having a central groove therein and stepped surfacesat each end, a first plurality of wire laterals extending across saidgroove: and defining an electrode, said wire laterals being electricallyconnected to said disc, a s'econd'plurality of wire laterals extendingacross said stepped portions, a flat cathode within'saidgroove andsuspended directly from'said second plurality of wire laterals adjacentsaid electrode-laterals, means electrically connecting said secondplurality of wires to said leads extending through said base, and meanslocking said block in position in said cradle member.

10. An electron discharge devicecomprising an envelope, said envelopecomprising an anodeportion, a cathode portion, and a disc therebetween,a plurality of leads extending through*said'cathode portion, a cradlewithin said envelope integral with said disc, an insulator support blockin said cradle, said block havinga planar'upper surface with steppedportions at each end and a groove centrally therein, a first pluralityof wirelaterals secured to said block and extending across said groovein the plane of said surface, said laterals defining an electrode andbeing electrically connected to said disc, a second plurality of wirelaterals secured to said block and extending across said groove in theplane of said stepped portions, a flat hollow cathode in said groove andsuspended from said second plurality of wires in the plane of saidsteppedportions adiacentsaid-elec trode laterals, tabs electricallyconnectingsaid cathode to one of saidleads extending through saidcathode envelope portion, a heater element extending within saidcathode, tabselectrically connecting said'heater element to other ofsaid leads extending through said cathode envelope portion, an anodeopposite said electrode la-terals to the other side thereof than saidcathode, lead means extending through said anode envelope portionsupporting said anode, and locking members extending across said blockat the ends of said planar surface and secured to said disc on each sideof said block, locking said block in position in said cradle.

11. An electron discharge device comprising an insulator block having aplanar surface and a roove centrally therein along the length of saidblock, said block also having a transverse groove adjacent each end, aplurality of wire laterals extending across said surface and secured tosaid block, a rod extending through each of said transverse grooves andacross said lengthwise groove, means accurately positioning said rods insaid transverse grooves and securing them to said block, and a flatcathode in said lengthwise groove and suspended directly from said rodsadjacent said wire laterals.

12. An electron discharge device comprising, an envelope, a discextending through Said envelope, a cradle member within said envelopesupported by said disc and electrically connected thereto, a ceramicblock positioned in saidcr'adle member, said block having a planarsurface 'a'nda groove centrally therein along the length of s'aidblock,said block also having a transverse groove adjacent each end, aplurality of wire laterals extending across said surface and secured to'saiubiock, said who laterals being electrically connected to 8 saidcradle member and defining an electrode, a rod extending through each ofsaid transverse grooves and across said lengthwise groove, meansaccurately positioning said-rods insaidtransverse grooves and securingthem to said block, a fiat cathode withinsaid lengthwise groovesuspended directly from said rods adjacent said wire laterals, an anodeadjacent saidelectrode to the other'side thereof than said cathode,means supporting said anode in said envelope and providing electricalconnection through said envelope therefor, means electrically connectedto said cathode providing electrical connection through said envelope,and

locking members extending across said block and securedto said cradlememberon each side of said bloc locking-said-block-in position in saidcradle member.

13. The method of fabricating electron =discharge devices whichcomprises winding a fine wire around a block having a planar-surfacewith stepped portions at each end and a groove -centrally therein,bonding said wire to said block, positioning a flat cathode in saidgroove, securing said cathode to the portions of said wire across saidstepped portions so that saidcathode is suspended therefrom, andseparating said wire portions extending across said stepped portionsiromthe portion extending across said surface.

14. The method of fabricating an electron discharge device whichcomprises winding a single wire across a support block having two planarsin'faces, securing said wireto said block, securing a flat cathode tothe portions of said wire across one of said planar surfaces so as to besuspended therefrom, and rupturing the connection between the portionsof said wire across'said two surfaces.

15. The method "of fabricating an electron discharge device whichcomprises winding a single line wire around a support block having 'agroove centrally therein securing saidwire to'said block, positioning afiat cathode in said groove, securing said cathode to securedportions'of said wire so as to be suspended directly therefrom,v andrupturing the'connection between said portions and the remainder of saidwire.

16. The method of fabricating an electron discharge device whichcornprises winding a single fine wire around an insulator block having agroove centrally therein, a p-lanai-"uppersurface and step portions atthe ends thereof honding'said wire to said block, positioning a flatcathode in said groove, securing said cathode to the portions of saidwire extending'across said stepped portions so that said cathode isdirectly suspended from said wire portions, rupturing the connectionbetween said wire portions and the-remainder of said wire across saidplanar surface, positioningsaid block in a cradle member, and lookingsaid block in saidcradle member.

EDWARD J. WALSH.

References Cited in the file of this patent UNITED STATES PATENTS Number7 Name Date 1,273,630 Langmuir Jul 23, 1918 2,380,525 Hirmann July 31,1945 2,413,006 Spencer Dec. 24, 1946 2,419,757 Binn'eweg, Jr Apr. '29,1947 2,503,806 Diggle Apr. 11, 1950 2,519,445 Drieschman Aug. 22, 1950

